Normal automobile tires are not suitble for driving on snow, when the road is inclined in a hilly or mountainous country. Special snow tires can be used where the snow covers the road for a longer period of time. They are expensive, take much storage space during warmer seasons and are not practical for those people who would need them only a few times in a year such as for a trip to the mountains during the winter. In addition these people would have to pay for installing the snow tires before the trip and then changing back to normal tires.
In order to overcome such difficulties the people use tire chains, which are satisfactory when the roads are covered by snow. However, when there is no snow or if the portions of the road are bare with the snow swept away by the wind, the chains are very noisy, damaging the road surface and can break. Even in the winter, on a busy highway the snow can be melted by traffic during the midday and bare surfaces can be exposed. The snow chains are difficult to mount on a tire because they are heavy and shapeless. When one end is placed over the tire, another person is needed to hold it because it would immediately fall down before the other end could be joined.